Self assembly techniques are being used to adsorb organic thin films onto gold and oxide surfaces. Both monomeric and polymeric components are used to form the organic thin films. The monomeric assemblies are comprised of alkane thiols (gold) and silanes (oxides) with varying degrees of fluorination. For thiols, the effect of the length of the fluorocarbon and hydrocarbon sections on assembly, orientation, and bonding in the resulting organic thin film is being examined. Initially films containing only one type of monomer are being examined [e.g., CF3(CF2)7(CH2)11SH]. In the future thin films prepared from mixtures of different monomers will also be examined. For silanes, the effect of surface coverage on chain orientation for vapor deposited fluorinated compounds [e.g., CF3(CF2)7(CH2)2SiCl3] is being examined. The polymeric system currently being studied is a dimethyl siloxane with three different concentrations of propyl thiol side chains. Film thickness, thiol distribution within the organic thin film, percent of thiol groups bound to the gold surface, and oxidation of the unbound thiol groups are being examined. After the monomeric and polymeric thin films have been fully characterized by NESAC/BIO (ESCA and static SIMS) and CPIMA (contact angle, ellipsometry, and FTIR) their biological performance (protein adsorption, protein retention, and cell growth) will be measured and correlated with the surface structure of the films.